Application Of Mussel-inspired Surface Interface Modification Technology In Marine Concrete Protection

Reasonable protective measures are of great significance to improve the durability of marine engineering concrete,and the basic protection and additional protection technologies of concrete developed for this need have made great progress in prolonging the service life of marine engineering concrete.However the mechanical properties of concrete are reduced and the waterproofness is insufficient due to the incompatibility between the surface and interface of organic and inorganic materials.In addition,the the problems of organic pollutants and microbial adhesion in the process of marine engineering concrete protection cannot be ignored.Thus,in this study,the mussel inspired surface-interface modification technology is proposed to modify marine engineering protective materials,and on this basis,the possibility of self-cleaning function of marine engineering concrete is explored.The specific contents are as follows:(1)Rubber-modified cement mortar(rubber cement mortar)with great potential in the basic protection of marine engineering concrete is selected as the research object.Starting from the problem that the interface incompatibility between rubber particles and cement matrix reduces the mechanical properties of rubber cement mortar,polyphenols such as dopamine are used to improve the interface bonding between rubber particles and cement matrix.The effects of polyphenol modification on the interfacial compatibility between rubber particles and cement matrix were systematically studied by static/dynamic contact angle,micro-morphology analysis,compressive test and friction test.The results show that polyphenol modification significantly improves the hydrophilicity of rubber particles and the interfacial bonding between rubber particles and cement matrix.After modification,the 28-day compressive strength of rubber cement mortar is improved by 37%.The simulated seawater immersion experiment shows that the water absorption rate of the modified rubber cement mortar for 7days is only 3.2%.In addition,polyphenol-modified rubber cement mortar shows excellent wear resistance in the range of-40?to 20?,which makes it better able to cope with physical wear such as sea wave scouring.(2)The polyacrylate coating commonly used for additional protection of marine engineering concrete was selected as the research object.Based on the principle of mussel bionic chemistry,the polyacrylate coating modified by strongly hydrophobic polyphenol propyl pyrogallol was designed,and the influence law of propyl pyrogallol modification on various properties of the coating was studied.The results show that the modification of propyl pyrogallol improves the paintability,adhesion and mechanical properties of polyacrylate coating,and the pencil hardness and adhesion test values of polyacrylate coating doped with 2 mg/ml propyl pyrogallol are increased from 3H and 2A to 5H and 5A respectively.Due to the hydrophobic effect of propyl pyrogallol,the waterproof property of polyacrylate coating mixed with propyl pyrogallol was obviously improved,and the water absorption rate of cement paste coated with modified coating decreased from 16.5%to 6.8%after being immersed in simulated seawater for 28 days.(3)In view of the problem that organic dirt and microbial adhesion aggravate the corrosion of marine engineering concrete,this thesis introduces two-dimensional material(Ti₃C₂ MXene)on the basis of modified polyacrylate coating,and prepares composite coating with self-cleaning performance,and explores the influence law of Ti₃C₂ MXene on the performance of composite coating.The results show that the addition of Ti₃C₂ MXene effectively increases the crosslinking density of polyacrylate coating,thus improving the mechanical properties,adhesion and water resistance of the composite coating.Ti₃C₂ MXene oxidizes to form Ti O₂/Ti₃C₂ with photocatalytic and photothermal activity,so the modified polyacrylate coating loaded with Ti₃C₂ MXene can not only effectively decompose oleic acid,but also inhibit the growth of Gram-negative/positive bacteria,and has self-cleaning performance.